wiki:
.22 WRF ammunition is periodically offered by commercial makers for use in the old guns.[1] It can be fired in any rifle chambered for the more powerful .22 WMR.[1]
Just found a website that featured the exact brand of ammo I bought. The bottom line of the article said you can’t use it in a rifle chambered for .22WRM because the .22WRF uses JHP’s. Not sure why but I have JHP’s in .22WRM specifically for the larger varmints that come up my way (coyote and bobcat).